Nursing techniques and diagnostic procedures for exotic animals (Proceedings)

Diagnostic endoscopy

Rigid endoscopy can be performed in many reptiles by passing the endoscope through the oral cavity and into the stomach. Endoscopy is primarily used to obtain gastric biopsies or to retrieve foreign bodies from the stomach.

Flexible endoscopes are commonly used to perform bronchoscopy in larger snakes and some larger small exotic mammals such as rabbits and ferrets. The procedure is very similar to that in dogs and cats.

Rigid endoscopy is often performed in birds to obtain diagnostic samples of organs such as lung, kidney, liver, adrenal glands, etc. This is considered a minimally invasive procedure and patient's generally recover quickly from the procedure.

Cloacal wash in reptiles

Cloacal washes are used to collect feces for laboratory analysis. This is very common as fresh stool is often not available in reptiles. A red rubber feeding tube of appropriate size is attached to a 1.0 mL syringe. The tube is well lubricated with a water based jelly and placed into the cloaca. Saline is infused into the cloaca and aspirated back out. This lavage will often yield enough fecal material for microscopic analysis. This not used in birds and exotic small mammals.

Nasal flush in avian species

A nasal flush can be useful for birds presenting with sinusitis, nasal discharge, or signs of upper respiratory disease. A cytological sample can be obtained by flushing warm saline into each nostril. The bird is held upside down with the head aimed toward the ground. A sterile urinary cup can be placed under the beak to catch the sample draining from the nasal cavity and sinuses.

Skin scrape and touch smears in exotic species

Performing skin scrapes or touch (impression) smears is an easy way to obtain information on potential bacterial and fungal infections of the skin. A cover slip edge is gently scraped across the skin and then placed on a slide with saline making a wet mount. This sample should be analyzed immediately to obtain accurate results. Skin scrapes should not be performed on specific lesions as this can cause more damage to the skin. A touch or impression smear is primarily used on specific lesions such as ulcers or other damaged tissue. A microscope slide is touched to skin in an attempt to collect histological data. The smear is then stained for analysis.

Tracheal wash in exotic species

The mouth is gently opened using an appropriate mouth speculum such as tape or gauze stipes or a plastic spatula. Using aseptic technique, the tracheal wash is performed by inserting a sterile red rubber feeding tube or polypropylene urinary catheter into the trachea. The patient must be anesthetized for the procedure as it can be very stressful and the tissues are delicate. Generally a small about of saline is infused and then aspirated from the trachea. The volume will depend on the size of the patient. The sample should be smeared onto a slide and stained for analysis. This is very similar to performing a tracheal wash in dogs and cats.

General parasitology techniques in exotic species

Exotic animals can be affected by a wide variety of parasites. There are several different ways to check for parasite load including direct fecal exam, fecal flotation, and cloacal wash (reptiles only). The direct fecal exam and flotation are done in the same manner as a dog or cat. The cloacal wash is accomplished by inserting a soft rubber feeding tube attached to a syringe into the cloaca. Saline is then flushed into the cloaca and suctioned out obtaining a diagnostic sample.

Radiology for exotic species

Good radiographs are an important tool used as part of your diagnostic work-up. The diagnostic value of a radiograph is dependent on the quality of the technique and positioning of the patient. Digital radiology is quickly becoming the standard in most hospitals and will yield the best results. However, if digital radiology is not yet available in your hospital then high detail, rare earth cassettes with single emulsion film provides desired results. Mammography film will produce even better detail, but does require a higher KVP and MA. A technique can be extrapolated from your tabletop technique used on most of your feline patients. For extremely small patients, you can utilize a dental radiology unit. If you have the luxury of a digital radiology machine, then you can use similar techniques with a few adjustments. Consult with a radiologist to update your technique chart if needed.

Snakes

Two views are normally taken which include a dorsoventral (DV) or ventrodorsal (VD) and a lateral. Radiographs are taken in sections from head to tail and labeled with numbered lead markers to delineate each section. In most cases the snake will need to be heavily sedated or anesthetized to take good radiographs, unless the snake is really sick. A plastic snake tube can be used to obtain radiographs, but often diagnostic films are not produced unless the snake is unable to move within the tube and remains completely straight.

Chelonians

Three views are normally taken which include a dorsoventral (DV), horizontal lateral, and horizontal craniocaudal views. A horizontal beam is essential to obtain good radiographs. Since chelonians do not have a diaphragm, placing them in lateral recumbency causes shifting of the organs into the lung cavity which leads to poor radiographs. Most chelonians do not need to be sedated for radiographs. In most cases the patient will just sit there or it can be placed on a plastic dish with its feet hanging in the air

Lizards

Two views are normally taken which include a dorsoventral (DV) and horizontal lateral. A horizontal beam is essential to obtain good radiographs. Since reptiles do not have a diaphragm, placing them in lateral recumbency causes shifting of the organs into the lung cavity which leads to poor radiographs. Most lizards do not need to be sedated for radiographs, but chemical restraint can be used if necessary. In most cases the patient will just sit there while the radiographs are being taken. You can also use vagal stimulation or the "vagal response" to calm the patient if needed. The vagal response in iguanas and other medium to large lizard species can be induced by gently applying digital pressure to both eyes for a few seconds to a few minutes. The patient will usually respond with a decrease in heart rate and blood pressure. The vagal response induces a short-term trance-like state allowing time to take radiographs and in some cases even draw blood.

A GI barium series can be performed in reptilian species. The barium is administered via a metal or red rubber feeding tube into the proximal esophagus. The mouth is gently opened using tape strips or a plastic spactula. GI transit time in reptiles is not well documented and can take several hours to days depending on the species. The barium series should consist of plain films (taken prior to barium administration), and films taken at 15 minutes, 30 minutes, and then every few hours post administration until done. Both a lateral and ventrodorsal whole body view should be taken for each time period. If the GI series is taking several hours, it is ok to continue the series the next day. You will need to play it by ear and make a guesstimate on how you will proceed. Often times only one or two radiographs will be taken per day until the barium series is complete.

Exotic small mammals

Sedation or general anesthesia is generally needed to take good diagnostic radiographs of exotic small mammals. Due to their size, whole-body radiographs are usually taken of the patient (although it is ideal to take separate thoracic and abdominal films). A complete radiographic series includes a ventrodorsal whole body radiograph and a left or right lateral whole body radiograph. Views of the limbs are taken in the same manner as dogs and cats. The patient is gently taped down to the x-ray table or directly onto the plate and positioned as necessary. The use of a sponge trough is helpful for positioning ventrodorsal views. It is often helpful to use high detail mammography film or digital radiography to obtain the best images. The positioning techniques used for dogs and cats are used for exotic small mammals as well. Sand bags are generally not used due to the size and weight.

A GI barium series can be performed in exotic small mammals, but it can be difficult to administer the oral barium. I find it easiest to attach the barium filled syringe to a metal feeding tube used for birds and slowly administer the barium into the mouth. The metal feeding tube is not placed down the esophagus, but it is placed in the corner of the mouth and the barium is slowly administered. The metal feeding tube seems to work better than using just a plain syringe and there is often less mess. The GI transit time in hindgut fermenting animals such as rabbits, guinea pigs, and chinchillas can take several hours (sometimes over 24 hours) while carnivorous animals such as ferrets can have a transit time of about an hour or less. The barium series should consist of plain films (taken prior to barium administration), and films taken at 15 minutes, 30 minutes, and then hourly increments post administration until done. In cases where GI transit time is lengthy it is advised to take films every 2 to 4 hours. Both a lateral and ventrodorsal abdominal view should be taken for each time period.

Birds

In general birds should be briefly anesthetized with either isoflurane or sevoflurane to obtain radiographs. Some people hand hold birds for radiographs, but this exposes the staff to unnecessary radiation, it is very stressful for the bird to be held down, and it increases the risk of fracturing a limb. Two views, the ventro-dorsal and right or left lateral whole body radiographs are commonly taken for a complete series. Whole body radiographs are commonly taken because the bird will fit on the plate and there is not a true delineation between the bird's "thorax" and "abdomen" (no diaphragm in birds). If you need to take limb radiographs, the x-ray beam should be coned down to just radiograph the wing or leg. A lateral and anterior-posterior (cranial-caudal) (leg) or posterior-anterior (caudal-cranial) (wing) radiograph should be taken for completeness. Regardless of the view, the animal should be positioned in a symmetric, straight fashion. If the bird is rotated, the radiograph will be hard to read properly and may not be diagnostic. Either digital film or mammography film work well for radiographing most species of exotic animals. The technique will vary from clinic to clinic and will be based on the type of film, processing techniques and machine used. A quick "bird in a box" technique can be used for birds that are either very sick and cannot handle the stress of being restrained or anesthetized. The bird is placed in a cardboard box or paper bag in the dorso-ventral standing position. This technique is only helpful for checking the patient for an egg, large coelomic mass/fluid, or metal foreign body.

A GI barium series can be easily performed in avian species. The barium is administered via a metal or red rubber feeding tube into the crop. The beak is gently opened using tape strips. GI transit time in most common pet birds can take about 30 minutes to about 6 hours (depending on species). The barium series should consist of plain films (taken prior to barium administration), and films taken at 15 minutes, 30 minutes, 45 minutes, and then hourly increments post administration until done. Both a lateral and ventrodorsal whole body view should be taken for each time period. Most birds should be sedated for this procedure.

Ultrasonography in exotic species

Ultrasonogrpahy can be a useful diagnostic tool in most species, but in birds, the airsacs and keel bone get in the way of getting a good look at many of the organs. Ultrasonography can also be utilized in reptiles and exotic small mammals. The same techniques used with dogs and cats are used with these species as well. Chelonians can be difficult due to the carapace and plastron. The ultrasound probe can be placed in the inguinal area after pulling the hind limb away from the body. You must be careful because chelonians are very strong and can easily destroy an ultrasound probe by pulling their leg back into the body wall. Lizards with thick scales can often be difficult to ultrasound due to poor image quality.

CT scans in exotic animals

CT machines are becoming more easily assessable and are often common in large referral hospitals and academic institutions. Performing CT in the exotic pet has become an important diagnostic tool. The scans are done in a similar manner as dogs and cats. Most patients will need to be anesthetized during the CT scan to prevent moving and general motion artifact. Chelonians are the exception. Most turtles and tortoises can simply be placed on a radiolucent bowl and taped down. As long as the animal's legs cannot touch the ground, they will stay in place long enough for a complete CT scan. Common CT scans include skull (dental disease in exotic small mammals), thorax, abdomen, and pelvis.